Polyols are materials used in a wide variety of applications, such as flame retardancy, cross-linkers, chain extender, chain terminators, and/or polyurethane synthesis. U.S. patent application publication 2008/0182944 (Benecke et al.) describes a series of new polyols used in formaldehyde free binders in fiberglass applications. Benecke et al. disclose that the new polyols are based on furan dicarboxylic acid (FDCA), and these polyols are disclosed to be useful as a binder. However, the current pricing of FDCA is too high for industrial use. Until FDCA is more cost effective, alternative polyols are needed.
Furan-containing polyols, compounds or materials (“furan compounds”) are known for their char formation when heated to high temperatures, and as such, they are regarded as possibly having some flame-retardant properties when combined with other known flame-retardants, cf. U.S. Pat. Nos. 4,029,611; 3,865,757; 4,318,999, and U.S. patent application publication no. US 2011/0124839. The other known flame-retardants are considered to be main contributor to the flame retardation properties of the foam; while the furan compounds were used along with other catalysts for promoting carbodiimide linkage so that the resulting foams could have better processability without losing any flame retardant properties (U.S. Pat. No. 4,029,611). These other commonly used flame retardants are phosphorus-containing inorganic compounds (U.S. Pat. No. 3,865,757), tris(2-chloroethyl) phosphate (U.S. Pat. No. 4,029,611), halogenated compound (U.S. Pat. No. 4,318,999), phosphorus element (U.S. patent application publication no. US 2011/0124839).
In other words, the flame retardation properties of the furan resins were not studied independent of the presence of other known flame retardants, the inclusion of which can increase the expense of the foam products and causing changes to the foam characteristics of the product. It is well known that cell structure of the foam and crosslinked polymers can affect the flame retardancy, such as the burning rate of the foam. According to Saber et al. in a 2010 report # RR291 to the National Research Council Canada, crosslinking bond strength of the flame retardant materials is important in flame retardation (the report is entitled “Numerical and Experimental Investigations of Fire Behavior of Polyurethane Foam and Wood Cribs in a Medium-Sized Residential Room”). The foam is a cross-linked polymer, and at an elevated temperature, the melting cannot occur until these crosslinks are broken. The crosslinks take several forms and the proportions depend on the particular foam formulation.
The bond strength of a furan compound is dependent its structure, or dependent on the addition of another flame retardant element, such as phosphorus. For example, Matsuda et al. disclose in U.S. patent application publication no. US 2011/0124839 that polyethylene 2, 5-furan dicarboxylate has been unable to achieve high flame retardancy such as V-0 or V-1 in UL94 Standard by itself. However, Matsuda et al. states that a polyester copolymer, which was formed by adding a furan diol or an aliphatic diol, and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to polyethylene-2,5-furan dicarboxylate (DOPO), had a increased flame retardant properties so that the burning test result for the copolymer corresponds to V-0 in UL94 Standard. As such, they conclude that “when the content of the phosphorus atom is from 0.3% by weight to 1.5% by weight,” the resulting furan copolymer shows a good flame retardancy (the burn test corresponds to V-O).
Therefore, the addition of other known flame retardants can affect the cell structure of the foam, and may provide additional crosslinked bonds that can also interact and/or crosslink with the furan resins/compounds. As such, the furan compounds might not contribute significantly, or if any, flame retardant properties to the resulting foam, especially at a low furan content, such as 4 wt % or lower.
In addition, these known furan compounds are commonly condensation products of furfuryl alcohol with formaldehyde in an acidic environment. At high temperatures, the foams with such furan resins will likely release formaldehyde, which can cause significant negative health effects because formaldehyde is a known toxic substance. There is increasing demand for phasing out the halogenated flame retardants (FR) because of high and toxic smoke generation.
A furan ring-containing polyol, 2-furoyldiethanolamide, is disclosed in U.S. Pat. Nos. 7,541,350; 7,144,845; 7,132,532; and U.S. patent application publication no. US 2009/015657. The patents and the patent application do not suggest or teach that the polyol might have flame retardant properties, nor are the patents and the patent application interested in the flame retardant property of the polyol or the typical uses of polyols as precursors for polyurethanes or polyesters. The polyol is described as a more water-soluble by-product of a formulation containing anti-inflammatory androstane derivative. The polyol's improved water solubility enabled the polyol to be removed by water washing, thereby providing an improved process for synthesis of a specific drug.